Phosphate-free detergent concentrates containing sulfated and sulfonated linear alkylphenols

ABSTRACT

DETERGENT CONCENTRATED SUITABLE FOR FORMULATION INTO COMPOSITION CAPABLE OF HEAVY DUTY WASHING PERFORMANCE IN THE ABSENCE OF PHOSPHATE BUILDERS ARE PRODUCED BY SULFATING AND SULFONATING A C16-24 ALKYL MONOALKYLPHENOL AND NEUTRALIZING THE PRODUCT.

United States Patent O1 3,836,484 Patented Sept. 17, 1974 PHOSPHATE-FREEDETERGENT CONCENTRATES CONTAINING SULFATED AND SULFONATED LINEARALKYLPHENOLS Mitchell Danzik, Pinole, and Ralph House, El Sobrante,Calif., assignors to Chevron Research Company, San Francisco, Calif.

No Drawing. Original application May 5, 1970, Ser. No. 34,885, nowPatent No. 3,697,573. Divided and this application Apr. 1, 1971, Ser.No. 130,449

Int. Cl. C11d 1/22, 11/04 US. Cl. 252-550 2 Claims ABSTRACT OF THEDISCLOSURE Detergent concentrates suitable for formulation intocomposition capable of heavy duty washing performance in the absence ofphosphate builders are produced by sulfating and sulfonating a C1644alkyl monoalkylphenol and neutralizing the product.

CROSS-REFERENCE TO RELATED APPLICATION This application is a division ofcopending application Ser. No. 34,885, filed May 5, 1970, now Pat. No.3,697,- 573.

BACKGROUND OF THE INVENTION This invention is concerned with novellinear alkylphenol sulfate-sulfonate compounds which are effective indetergent applications as detergent actives.

Increased concern over water pollution has produced significant changesin household detergents. Initially, major emphasis has been placed onproducing biodegradable surface-active components for detergents. Theshift to linear surface-active materials, including linear alkylbenzenesulfonate (LAS) and alpha-olefin sulfonates, etc., has reduced pollutionattributed to nonbiodegradability.

However, the above-mentioned surface-active materials are inadequate interms of soil removal in the absence of phosphate builders. Increasingevidence appears to indicate that phosphates contribute to the growth ofalgae in the nations streams and lakes. This algae growth poses aserious pollution threat to the maintenance of clear, good domesticwater supplies.

Consequently, there has developed a need for detergent active materialswhich will function successfully in the absence of phosphate builders.Recently, certain nonphosphate building materials have been proposed asreplacements for the phosphates. Thus, materials such as the polysodiumsalts of nitrilotriacetic acid, ethylene diamine tetraacetic acid,copolymers of ethylene and maleic acid, and similar polycarboxylicmaterials have been proposed as builders. These materials, however, whenemployed with conventional detergent actives such as LAS, have, for onereason or another, not proved to be quite as effective as phosphates indetergent formulations. For example, some of the materials have provento be insufficiently biodegradable to meet present and anticipatedrequirements.

It is therefore desirable to provide compounds which are effective asdetergent active materials in the absence of phosphate builders and aresufficiently biodegradable that their use does not contribute foam tothe water supply.

In addition, in the past, with heavy duty detergents, it has beenthought that to achieve good soil removal it was necessary to maintain ahigh pH in washing solutions. This concept, which began with thestrongly alkaline laundry soaps, has continued to the present day LAS-phosphate combinations which are in widespread use in heavy dutydetergent formulations. One apparent reason for this is that thealkylbenzene sulfonate detergents are not effective in heavy dutydetergent formulations in the absence of a builder. The phosphatebuilders, for example, must be employed at a pH greater than 9 to beeffective. and even the newer builders such as sodium nitriloacetatc:have a pH of about 9 in solution. The advantages to be gained with heavyduty detergents which may be em ployed at neutral pH are many.Deleterious effects from skin contact are lessened. Enzyme-type soillooseners may be more easily combined in neutral solutions. Injury tofabrics is minimized. It is, therefore, desirable to provide detergentactive materials which, in addition to the previously mentionednon-polluting characteristics, achieve their maximum detergency at ornear neutral pH.

The formulation of liquid heavy duty detergent compositions achievesmany desirable results. They are easy to package and measure, and theiruse opens the possibility of automatic dispensing in washing machines.However, in the past it has been impracticable to formulate heavy dutydetergents in liquid form because of the insufficient solubility of theinorganic ingredients (phosphate builders, etc.) required for heavy dutyapplications and the high cost of organic substitutes for such inorganicingredients. It is therefore highly desirable to provide detergentactive materials having good Water solubility and which, because oftheir excellent detergency without builders, can be formulated intoeffective, reasonably priced, heavy duty liquid detergent formulations.

SUMMARY OF THE INVENTION Heavy duty detergent materials are providedwhich comprise alkylphenol sulfate-sulfonates of the formula OSO X inwhich R is a substantially linear alkyl group of from about 16 to 24carbon atoms and X is H or a watersoluble salt-forming cation.

The compounds of this invention do not require the presence of a builderto achieve good heavy duty detergency, and while they are effective overa broad pH range, reach their maximum effectiveness at a pH near neutralin detergent solutions. Thus washing at a pH of 6.5 to 8.0, preferably6.5 to 7.5, will give maximum soil removal while securing the previouslymentioned advantages which inhere in the use of neutral washingsolutions. Further, the compounds may be easily compounded intoefiective liquid heavy duty formulations because of the substantialsolubility of the compounds in water and because of the lack of need forlarge adjunctive portions of inorganic materials such as builders.

DESCRIPTION OF PREFERRED EMBODIMENTS The salt-forming cation X may beany of numerous materials such as alkali metal, alkaline earth metal,ammonium, or various organic cations. Examples of suitable organiccations include nitrogen-containing organic cations such asdiethanolammonium and triethanolammonium cations. The alkali metalcations are preferred, and sodium ions are particularly preferred.

The alkyl groups represented by R are, as previously noted,substantially linear, although the presence of a random methyl radicalupon the linear chain, for example, may not adversely affect theperformance of the compounds. Alkyl radicals representative of R includehexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl,docosyl, tricosyl, and tetracosyl. The preferred com- 3 pounds will haveas alkyl substituents octadecyl, nonadecyl, and eicosyl groups.

The alkylphenols which are suitable for the preparation of the compoundsof this invention are prepared by conventional techniques. Suchtechniques include thermal and catalytic alkylation of phenol witholefins, alcohols and haloparafiins. Catalytic methods include the useof Friedel- Crafts catalysts such as aluminum chloride, zinc chloride,etc., and various acid catalysts and clay catalysts.

The alkyl groups are generally derived from alcohols, olefins, orhaloparaflins. The position of the attachment of the aromatic nucleus onthe alkyl chain may be at any point. With alpha olefins the predominantpoint of attachment of the alkylation product will be end groupattachmentthat is, either at the l or 2 but principally at the 2position of the chain. On the other hand, with an isomerized mixture ofolefins, or olefins derived from haloparaffins which have, jn turn, beenproduced by halogenation of parafilns, the position of the double bondwill be generally completely random on the chain, and thus thecorresponding aromatic nucleus attachment will be randam.

The sulfonation and sulfation of the alkylphenols to produce thecompounds of this invention is accomplished by reacting the alkylphenolwith a sulfonating agent capable of 1) converting the aromatic hydroxylradical to a sulfate and (2) forming a ring-substituted SO H underconditions such that the reaction product contains both an -OSO H and an-SO H radical attached to the aromatic nucleus. The preferredsulfonating agent satisfying these reaction prerequisites is sulfurtrioxide. The sulfur trioxide may be employed in mixtures with anappropriate liquid solvent such as a chlorinated hydrocarbon or liquid SComplexed S0 may also be used to effect the reaction. Typical complexingagents are dioxane and dimethylaniline, triethylamine, etc.

In contrast, the reaction of the alkylphenol with sulfuric acid, oleum,or chlorosulfonic acid under conventional sulfonation conditions doesnot result in any appreciable yields of the correspondingsulfate-sulfonate.

The alkylphenol sulfate-sulfonate compounds of this invention thus aresuitably prepared by the reaction of an alkylphenol with sulfurtrioxide. The reaction is. carried out in an anhydrous inert solventsuch as the chlorinated hydrocarbons, e.g. dichloroethane. The quantityof sulfur trioxide to be used should equal or exceed 2 moles per mole ofalkylphenol for 100% conversion of the latter. Mole ratios of S0 toalkylphenol as high as 10:1 may be employed, but preferably the ratio isin the range of 3:1 to 5:1. At mole ratios below 2:1, some of thedesired alkylphenol sulfate-sulfonate will be formed, but depending onthe mole ratio used, substantial amounts of mono sulfonated materialwill be formed. Reaction temperatures are generally in the range of to10 C., preferably about 5 to 0 C. Alkylphenol, dissolved in the solventis cooled to the reaction temperature and then S0 dissolved in the samesolvent is added. The reaction is exothermic, and cooling means must beemployed to keep the temperature within the desired range. The rate ofaddition of S0 is such that the cooling means can hold this temperature.Thus the time required for reaction varies as to efliciency of cooling,size of reaction mass, etc., but generally the addition will be completewithin 10 to 120 minutes for small sized batches. Continuous procedureis preferred for large batches. In continuous processing, the reactants,dissolved in an appropriate solvent and cooled to reaction temperature,are charged to a cooled tubular reactor, wherein the average residencetime is only a few minutes or less.

After sulfonation, the reaction product may be neutralized with awater-soluble, salt-forming cationic neutralizing agent, usually a metaloxide or hydroxide, and more preferably an alkaline earth metal oralkali metal hydroxide. The alkali metal hydroxides are preferred, andsodium hydroxide is most preferred. In addition to the inorganic basesdescribed above, the neutralizing agent may be any of various organicbases. Sufficient base is added to neutralize both acid sites, that isabout two moles. The final pH of the neutralized mixture should be about7, but pH values Within the range of 6 to 8 are satisfactory.

Following neutralization, the inert organic solvent is removed forreuse. This may be done by phase separation, or preferably bydistillation. The organic solvent free material comprises an aqueoussolution of the organic surface active materials and any inorganic salt,such as sodium sulfate. The neutralized product, which will contain asubstantial quantity of water and from 1 to 4 parts of a normallyinorganic sulfate from the neutralization of excess S0 (e.g. N32804:),may be used, as is, in combination with conventional detergent additivesto formulate liquid heavy duty detergents. Alternatively, water may beremoved in any quantity to complete dryness by conventionalconcentration techniques such as evaporation, distillation, drum drying,etc., to yield a concentrated s0lution, a slurry, or a dry particulatesolid which may then be blended to form a heavy duty detergent.

The solid product isolated as described above may be desalted by theusual procedures as used in the alkylbenzene sulfonate art. In thismethod the solid material is mixed with about a 70/30 alcohol/Watersolution. The insoluble inorganic sulfate is removed by filtration, andthe organic surfactant may be used as such or isolated by evaporation ofthe solvent. The liquid concentrates and slurries may be treated insimilar fashion with allowance made for the quantity of Water alreadypresent. These desalting procedures give a detergent product that isessentially free of inorganic salt.

The following examples describe the preparation of the compounds of thisinvention.

Example 1.Preparation of Octadecylphenol Sulfate-Sulfonate To a 20 ml.reaction vessel fitted with a septum, drying tube, thermometer, and amagnetic stirring bar, was charged 1.0 g. (0.00289 mols) of a Calkylphenol which had been prepared by thermal alkylation of phenol witha linear C alpha olefin according to the procedure of US. Pat.3,423,474. A 10 ml. portion of dry 1,2-dichloroethane was charged to thereaction flask. The solution was flushed with nitrogen and stirring wasbegun. The solution was cooled to 10" C. in an ice-acetone bath.

A solution of 1.0 ml. anhydrous sulfur trioxide (1.9 g., 0.0237 mols) in5 ml. of dry 1,2-dichloroethane was cooled to about 0 C. The solutionwas injected into the reaction solution with a syringe at such a rate asto maintain the reaction temperature at about 0 C. After the additionwas complete, the cooling bath was removed, and the reaction mixture wasallowed to warm to room temperature over a period of about fifteenminutes. It was then added to 50 ml. of 0.5 N NaOH solution and titratedto a pH of about 10 with additional 0.5 N NaOH. The mixture was thenplaced upon a rotary evaporator, and the organic solvent was removedunder vacuum at 2530 C. The remaining water solution was diluted to 500ml. and titrated by a standard Hyamine procedure 1 giving about a yieldof octadecylphenol sulfate-sulfonate. Dilute acid hydrolysis followed bytitration showed that the primary product contained both sulfate andsulfonate groups in substantially equal amounts; that is, it was analkylphenol sulfate-sulfonate.

An infrared spectrum of the product showed strong adsorption in the1020-1070 cm? and in the 1200-1280 cm. regions.

Example 2.Preparation of Additional Linear AlkylphenolSulfate-Sulfonates lollowing the general procedure of Example 1,materials were prepared by employing as precursors a series (13%;?method of House and Darragh, Anal. Chem, 26, 1492 Example 3.Drying ofAqueous Alkylphenol Sulfate-Sulfonate Solution An aqueous solution ofoctadecylphenol sulfate-sulfonate prepared as described in Example 1 wasneutralized with sufficient sodium hydroxide to give a pH of 7. Thedichloroethane was removed by heating under vacuum at about 25-30 C. Thetemperature was then raised, and all of the water was removed to leave aparticulate solid mass Weighing 5.15 g. Analysis showed that thismaterial contained 31% octadecylphenol sulfate-sulfonate, a small amountof water, and the remainder sodium sulfate. The above isolated solid wasa free-flowing powder.

The compounds of this invention are useful as heavy duty detergentactives. In the past, heavy duty detergent formulations useful forremoving soil from textiles have comprised an organic surfactant(detergent) and an inorganic phosphate builder; the phosphate beingpresent by weight, in an amount of from one to four times that of thedetergent. The compounds of the present invention are excellent soilremovers without the aid of any phosphate builder. That is, thecompounds of this invention satisfy all need for both organic surfactantand builder in the final heavy duty detergent formulation. One way thatthis may be accomplished is by preparing a mixture of thesulfate-sulfonate materials of the instant invention and an inertmaterial, e.g. water, sodium sulfate, sodium carbonate, etc. Suchmixtures may contain any amount of sulfate-sulfonate in excess of aboutpreferably or more. One useful composition comprises from 30 to 50%sulfate-sulfonate and the remainder, sodium sulfate. Many othercombinations make useful formulations and may be either liquid solutionsor particulate solids.

As heavy duty detergents, it is contemplated that the sulfate-sulfonatecompounds will be used in wash water at concentrations of about 0.01% toabout 0.10%. This is within the same range of concentrations as areemployed with the present day commercial detergents. In other words, thesoil removal properties of the present compounds are essentiallyequivalent to the soil removal properties of an equal amount of thecurrent commercial surfactant combined with at least an equal amount ofphosphate.

Detergency of the compounds of the present invention is measured bytheir ability to remove natural sebum soil from cotton cloth. By thismethod, small swatches of cloth, soiled by rubbing over face and neck,are washed with test solutions of detergents in a miniature laboratorywasher. The quantity of soil removed by this washing procedure isdetermined by measuring the reflectances of the new cloth, the soiledcloth, and the washed cloth, the results being expressed as percent soilremoval. Because of variations in degree and type of soiling, in waterand in cloth, and other unknown variables, the absolute value of percentsoil removal is not an accurate measure of detergent elfectiveness andcannot be used to compare various detergents. Therefore, the art hasdeveloped the method of using relative detergency ratings for comparingdetergent efiectiveness.

The relative detergency ratings are obtained by comparing andcorrelating the percent soil removal results from solutions containingthe detergents being tested with the results from two defined standardsolutions. The two standard solutions are selected to represent adetergent system exhibiting relatively high detersive characteristicsand a system exhibiting relatively low detersive characteristics. Thesystems are assigned detergency ratings of 6.3 and 2.2, respectively.

By washing portions of each soiled cloth with the standardizedsolutions, as well as with two test solutions, the results can beaccurately correlated. The two standard solutions are identical informulation but are employed at diiferent hardnesses.

STANDLARD SOLUTION FORMULATION Ingredient: Weight percent Linearalkylbenzene ulfonate (LASS) 25 Sodium triphosphate 40 Water 8 Sodiumsulfate 19 Sodium silicate 7 Carboxymethylcellulose 1 The standardexhibiting high detersive characteristics (Control B) is prepared bydissolving the above formulation (1.0 g.) in one liter of 50 p.p.m. hardwater (calculated as calcium carbonate and magnesium carbonate). The lowdetersive stanrdard (Control A) contained the formulation (1.0 g.)dissolved in one liter of p.p.m. water (same basis).

A miniature laboratory washer is so constructed that four differentsolutions can be used to wash diiferent parts of the same swatch. Thisarrangement ensures that all four solutions are working on identicalsoil (natural facial soil). Relative detergency ratings (RDRs) arecalculated from soil removals (SRs) according to the equation:

percent SR percent SRControlA percent SR percent SR A Detergency resultsobtained on a variety of the subject compounds are given in thefollowing table. Each value shown is the average of at least four tests.For comparison, the detergency rating is given for a linear alkylbenzenesulfonate (LAS) (having from 11 to 14 carbon straight chain alkylgroups) both with and without phosphate builder.

Each formulation tested comprised 25 weight percent of the test materialalong with 1% carboxymethylcellulose, 7% sodium silicate, 88% water, and59% sodium sulfate. The LAS comparison formulations were prepared in thesame way except that in Test 2 60% of the sodium sulfate was replaced byan equal amount of sodium tripolyphosphate and only 20% of LAS was used.The formulations were tested at several concentrations in water rangingfrom 0.1 to 0.2 weight percent. These concentrations were chosen inorder to bracket the 0.15% concentration typical of household use. Thetest results were obtained at a pH of 7, except for the two LASexamples, which were run at a pH of 9 (without phosphate) and 10 (withphosphate).

TABLE-DETERGENT EFFECTIVENESS OF LINEAR ALKYLPHENOL SULFATE-SULFONATESRDR=2.2+4.1

Relative detergency ratings (at indicated formulation concentrations) 50p.p.m. H20 180 p.p.m. 1120 Test N0. Compound tested 0. 10 0. 15 0.20 0.15

1 Linear alkylbenzene sul- 2.2 3.2 4.1 1.4

ionate (11-14 carbon atoms in the alkyl chain) (LAS). LAS (20%)lsodium5. a 5.7 6.0 3. 7

tripolyphosphate (40%). 3.-." Octadecylphenol sulfate- 4. 9 5.3 5. 6 4.4

s onate 4 Hexadecylphenol sulfate- 3. 3 4. 8 3.9

sulfonate. 5. Tetradecylphenol sulfate- 3. 6 2. 4

sulionate; 6 Eicosylphenol sulfate- 4.9 5.7 5. 9 4.7

sulionate. 7...-.. Docosylphenol sulfate- 5. 0 5. 4 4. 2

sulfonate.

These data show that the alkylphenol sulfate-sulfonates of thisinvention are greatly superior to phosphate-free LAS and aresubstantially equivalent to phosphate-built LAS in detergency. Moreparticularly, it may be noted that the compounds are very effectivenon-phosphate detergents and are particularly effective in hard water.

It will be understood that the effective compositions of this inventioninclude those materials which comprise a mixture of the al'kylphenolsulfate-sulfonates in which the alkyl groups vary in their carbon chainlength between 16 and 24. Thus in most instances a single species inthis respect will not be practical commercially and generally mosteffective compositions will comprise mixtures wherein at least 10 andpreferably at least by weight of at least two species of the alkylphenolsulfate-sulfonates are present in which R is an alkyl radical of 16, 17,18, 19, 20, 21, 22, 23 or 24 carbon atoms. The preferred range of carbonatoms in the mixtures will be from about 18 to 22 and most preferablyfrom about 18 to carbon atoms.

The alkylphenol sulfate-sulfonates may be employed in combination withother detergent active materials. They are particularly effective withother dianionic materials, examples of which include linear alkyl andalkenyl disulfates and disulfonates. A particularly useful class ofmaterials for use in detergent active combinations is that of linearZ-alkenyl or linear 2-alkyl 1,4-butane diol disulfates in which thealkenyl or alkyl groups contain from 15 to 20 carbon atoms. Anotherparticularly etfective class of materials are the alkylphenoldisulfonates described in our previously mentioned copending patentapplication.

In employing the detergent active materials of this invention indetergent compositions, they may be formulated with additionalcompatible ingredients being optionally incorporated to enhance thedetergent properties. Such materials may include but are not limited toanticorrosion, antiredeposition, bleaching and sequestering agents, andcertain organic and inorganic alkali metal and alkaline earth metalsalts such as inorganic sulfates, carbonates, or borates. Alsononphosphate builders may be included in the composition. Examples ofthese builders include the sodium salts of nitrilotriacetic acid,ethylene diamine tetraacetic acid, and ethylene-maleic acid copolymers,etc. Also small quantities of phosphate builders may be included in thecompositions, although, of course, they are not necessary for effectivedetergency.

While the character of this invention has been described in detail withnumerous examples, this has been done by way of illustration only andwithout limitation of the invention. It will be apparent to thoseskilled in the art that modifications and variations of the illustrativeexamples may be made in the practice of the invention within the scopeof the following claims.

We claim:

1. A heavy duty detergent active blending concentrate suitable forformulation into finished heavy duty detergent compositions obtained bythe process which comprises reacting one mol of monoalkylphenol in whichthe alkyl radical is substantially linear and contains from 16 to 24carbon atoms, with from 2 to 10* mols of sulfur trioxide at atemperature in the range of 10 to 10 C., (1) converting the aromatichydroxyl radical to a sulfate and (2) forming a ring-substituted SO' Hand thereafter neutralizing the reaction product with an alkali metal oralkaline earth metal oxide or hydroxide to a neutral pH wherein thereaction of sulfur trioxide and alkylphenol is carried out in thepresence of a chlorinated hydrocarbon solvent.

2. The heavy duty detergent concentrate of Claim 1 in which thechlorinated hydrocarbon is dichloroethane.

References Cited UNITED STATES PATENTS 2,190,733 2/1940 Richmond 260'4572,283,437 5/1942 Hentrich et a1. 26O--457 3,423,474 1/1969 Anderson eta1. "260-624 3,619,123 11/1971 Walz et a1 260457 X LEON D. RO'SDOL,Primary Examiner P. E. WILLIS, Assistant Examiner US. Cl. X.R.

